Device and method for monitoring and regulating a process solution

Abstract

Disclosed are a device and a method for continuously monitoring and regulating a process solution or the concentration of additives in a process solution, which influence the surface tension, particularly surfactants, in permanently operating industrial cleaning, coating, and rinsing installations, based on measuring the surface tension according to the bubble pressure method. Units detecting the surface tension or the concentration of a process additive in a process solution, processing and controlling a predefined internal program flow of the device, continuously monitoring the quality of a process solution, and triggering an external unit influencing the process are coordinated by means of an intelligent computer system which independently extracts and processes process data, uses the data for modifying the program flow thereof, exchanges the data with an external process control system, and influences the process.

1 . Device for continuously monitoring and regulating a process solution or the concentration of additives to a process solution, particularly surfactants, in continuously operating industrial cleaning, coating, and rinsing systems, based on measuring the surface tension of the process solution according to the bubble pressure method, wherein units for detecting the surface tension or the concentration of a process additive in process solution, for processing and regulating a predefined internal program sequence of the device, and for continuously monitoring the quality of process solution, and turning on an external device ( 23 ) that influences the process, are coordinated by means of an intelligent computer system that independently extracts and processes process data, uses said data for modifying its program sequence, exchanges the data with an external process control system ( 22 ), and influences the process, wherein the computer system contains the following memory contents in a memory, which contents can be preset by the process control system, manually, and/or by the device itself: 
 process sequences for cleaning, calibration, and measurement at various bubble lifetimes,    algorithms for extracting and processing measurement values, calibration curves, and cleaner-specific concentration series, and    inherent measurement values, including the circumstances under which they were extracted.    
     
     
         2 . Device for continuously monitoring and regulating a process solution or the concentration of additives to a process solution, particularly surfactants, in continuously operating industrial cleaning, coating, and rinsing systems, based on measuring the surface tension of samples of the process solution according to the bubble pressure method, wherein units for automatically detecting the surface tension or the concentration of a process additive in process solution, for automatically processing and regulating a predefined internal program sequence of the device, and for automatically and continuously monitoring the quality of process solution, and automatically turning on an external device ( 23 ) that influences the process, and for automatic communication with an external process control system ( 22 ) are brought together, both functionally and structurally, to form an autarkic unit ( 1 ) in a housing ( 1   a ), and wherein the device for detecting the surface tension or the concentration of process additive at least comprises: 
 a measurement vessel ( 3 ) having a program-controlled inflow and outflow supply device ( 7 ,  10 ,  11 ) for a program-appropriate exchange of rinsing liquid, calibration liquid, and sample(s) in the measurement vessel ( 3 ),    a measurement capillary ( 13 ) in the measurement vessel ( 3 ),    a program-controlled supply device for supplying the measurement capillary ( 13 ) with measurement gas,    a pressure sensor for determining parameters of the bubble pressure of the gas bubbles that exit from the measurement capillary ( 13 ), in the calibration liquid and in sample(s),    connectors/interfaces ( 21 ) for electrical operating current, for signaling states of the device, of process sequences and/or or process solution, for the external process control system ( 22 ), as well as for hoses/pipes ( 8 ,  9 ,  12 ) for liquids.    
     
     
         3 . Device according to  claim 2 , characterized in that 
 the measurement vessel ( 3 ) has cleaning liquid, calibration liquid, and sample(s) flowing through it, one after the other, in the cleaning mode, the calibration mode, and the measurement mode, in accordance with the program.    
     
     
         4 . Device according to  claim 2 , characterized in that 
 the measurement vessel ( 3 ) is structured in flow-minimized manner in the region of the measurement capillary ( 13 ).    
     
     
         5 . Device according to  claim 2 , characterized in that 
 the measurement vessel ( 3 ) holds diverted sample of a process solution in the measurement mode of the device, or diverted samples of several process solutions, in alternating manner.    
     
     
         6 . Device according to  claim 2 , characterized in that 
 sample and/or cleaning liquid and/or calibration liquid run into the measurement vessel ( 3 ) under program control, under gravitational pressure or transport pressure or line pressure, and that the media flow out of the measurement vessel ( 3 ) by means of gravitational pressure or transport pressure.    
     
     
         7 . Device according to  claim 2 , characterized in that 
 the device for detecting the surface tension is mounted in such a manner that it is uncoupled from vibrations.    
     
     
         8 . Device according to  claim 2 , characterized in that 
 the measurement capillary ( 13 ) is attached by means of a quick-close mechanism ( 13   d ), so as to be easily replaceable.    
     
     
         9 . Device according to  claim 2 , characterized in that 
 the measurement capillary ( 13 ) is hydrophobic, is slanted relative to the sample surface at the bubble exit, and has a support ring ( 13   b ) for bubbles that tip off.    
     
     
         10 . Device according to  claim 2 , characterized in that 
 an ultrasound emitter is arranged in the measurement vessel ( 3 ) for impacting the measurement capillary ( 13 ) with ultrasound, in the cleaning mode.    
     
     
         11 . Device according to  claim 2 , characterized in that 
 a temperature sensor ( 29 ) is arranged close to the capillary.    
     
     
         12 . Device according to  claim 2 , characterized in that 
 additional sensors for detecting additional measurement variables, such as conductivity, turbidity, and pH are integrated into the device, and processed by the latter.    
     
     
         13 . Device according to  claim 2 , characterized in that 
 a display and control panel ( 18 ,  19 ) for displaying and calling up measurement values and system states is arranged in the housing ( 1   a ).    
     
     
         14 . Device according to  claim 2 , characterized in that 
 one or more interfaces ( 21 ) for directly connecting one or more external process regulating devices ( 23 ) is/are provided.    
     
     
         15 . Method for continuously monitoring and regulating a process solution or the concentration of additives to a process solution, particularly surfactants, in continuously operating industrial cleaning, coating, and rinsing systems, based on measuring the surface tension of the process solution according to the bubble pressure method, using a device according to  claim 2 , wherein the dynamic surface tension of a process solution is automatically measured according to a differential pressure method, at a measurement capillary ( 13 ), in that the difference between the maximum bubble pressure and the minimum bubble pressure of a bubble is detected and evaluated at different surface ages that can be set.  
     
     
         16 . Method according to  claim 15 , wherein a process solution is automatically measured according to a method in which the bubble surface of a bubble is kept constant.  
     
     
         17 . Method according to  claim 15 , characterized in that 
 several similar sensors provide redundant measurement values for at least one measurement variable.    
     
     
         18 . Method according to  claim 15 , characterized in that 
 standing or flowing sample(s) is/are tempered before the measurement.    
     
     
         19 . Method according to  claim 15 , characterized in that 
 several process solutions are alternately monitored and regulated with a single device.